Venomous

This year I'm going to change the drive/ engine oil and engine filters myself. The question. I know how to drain the outdrive (the screw is located behind the propeller) but I need to know how to fill it. I have an oil reservoir for each of the drives that sits on the side of each engine. Can I fill the drive through the oil reservoir or do I have to buy a pump and force the oil back through the screw hole drain? I obviously want to do this right and do not want any air trapped inside the drives. So any advice is appreciated.

Thanks!

HiPerf2000

Fill from the bottom. It gets a bit messy trying to put the plug back in. Make sure you don't loose the rubber gasket that sits on the face of the plug.

Do a quick search on the subject. There is alot of info here.

CigDaze

You have to fill it from the bottom, otherwise you will never be able to completely purge all the air pockets.

With the vent screw removed start filling from the bottom. When oil begins to flow out of the vent hole, replace the screw and continue filling until oil appears in the reservoir. Then quickly remove the pump and replace the fill screw.

Then top off the reservoir.

There will still be some air trapped but it will be purged in the first few minutes running the drive. After those first few minutes, stop and top off again.

That should do it.

Cattitude

Not to open a can of worms.....

Can someone explain why you fill from the bottom- making a technical case for it? I'm betting this is the proverbial old wives tale.

I personally pull the top cap on my bravo and fill from the top- this gives me a glimpse of some teeth and the overall upper cavity. I glimpse at the res and check engine oil every time I raise the hatch to switch the batteries on. This fills faster with less mess and I don't have to buy some POS cheapy pump. I don't even have to pull the side plug cause you can clearly see it from the inside.

Forgive me for being simplistic and logical- if you fill from the top, it drains to the bottom and the level rises from the bottom- same net result.

As for trapping the air legend, if it's there to be trapped (a cavity with no vent on top) it will trap air either way- think about it.

Please, don't give me a well intended "Merc says" or "I've always done it that way". Perhaps there was a sound reason for another drive application, I don't know.

I'm betting the simple reason is to be less intrusive/easier for the average guy, one hole to fill from (bottom) leaving the upper hole free to confirm you hit the level (no hint of oil till it's full).

Can anyone make a sound case for bottom feeding- other than the average guy thing I suggested?

p4-33

Konrad Marine recommends theirs be filled from the top. But then again, their oil passages are large enough to drive a car through. I understand that the Alphas and Bravos have small oil passages, so there's a chance of air pockets with the heavier 80 or 90wt oil.

Konrad's hold 6+ quarts of oil each, so pumping from the bottom would take forever. I dump it in from the top, spin the prop in both directions a few times, let things settle, and top it off. Then I add to the reservior bottle until I see it draining into the top of the drive, and install the cap.

Iggy

Don't know about the Bravo drive but on the Alpha there is just one very small passage (1/4", maybe 5/16"?) between the upper and lower sections for oil to pass. Filling it from above would be next to impossible. I could never get all the air out.
Either way, there are far too many places for air to get trapped when filling from above. Filling from bottom up will purge the air pockets as it fills.

Lmarth

I'll repeat what I said here a year ago. I took the hose and fittings from the Merc "Ketchup Pump" and attached them to my reversible oil changer (clean hoses/container). I fill the container with lube, flip the switch and wait for it to come out the top while slowly turning the prop shaft. Did my SSM's yesterday quicker than you-know-what. For what it's worth.